Water and gas are supplied to domestic and commercial properties by way of large underground (mains) pipes which are laid by the utility suppliers. Smaller pipes connect the mains pipe to the individual building or dwelling. To enable the water or gas supply to be cut off from a particular building (in the event of a leak upon that property), the smaller pipes contain a valve or stopcock, the stopcock usually being located (underground) at the edge of the user's property, for example at the end of the driveway serving the property. Access to the stopcock is provided by way of an access hole.
Waste water is removed from domestic and commercial properties by way of underground waste water pipes, the waste water pipes forming a network joining each property to a waste water treatment facility. Access holes are provided at intervals along the pipe, the larger access holes (for the larger pipes) being manholes which are large enough to accommodate a person.
It is periodically necessary to replace an underground pipe, for example a pipe providing water to the property may become insufficient if the water consumption for the property grows beyond the capacity of the pipe. Also, a water or gas supply pipe, or a waste water pipe, may become damaged and start to leak, and so require replacement. In addition, it may be necessary to pass a cleaning tool along a pipe, for example to remove limescale encrustation within a waste water pipe.